@Volume... there are NOT 8 CELLS there are 24!
each "cell"is 3 sub-cells in parallell. These could easily be connected together by attaching each sub-cell to it's main cell-buses with appropriately low-melting point fusible straps....thus any individual cell that went defunct would not compromise the output voltage of the battery-unit.- it would, however, limit current-drawboth safe continuous and peak.
@ Machinbird...As already said by Momo....you can't credit engineers who merely make a gigantic Kludge to sidestep a fundamental problem.
@ Wiley B... they'll probably point the vent-pipes aft and sell it as "emergency auxiliary thrust"
@ Inetdog.."several starts" NO!!!! there has to be a half-hour cooling-period between APU runs, therefore one start and it recharges it's battery before shutting down. ('cos the batteries charge real quick(when they're not locked out because the start took the voltage too low
)
SEVERAL ATTEMPTED STARTS may be a different issue and one would question the Captain's decision to go with a dodgy APU.
I suggested Ceramic insulation a long while ago. the general concensus is that wound cylindrical cells are more robust. ceramic pota with screw-on ceramic lids could contain each sub-cell and individual cell temp and voltage-monitors the main cell-casing , similar construction. tails from sub-cells in suitable low melting alloy.
whole battery would thus maintain it's integrity and fulfill an emergency power role until all 3 individual sib-cells in a cell-pack had disconnected themselves, thus open-circuiting the whole battery..
Oh, Wait!! we" only" have 16,000 USD per battery , to play with...thermistors are HOW MUCH? Microchips /CPU's are HOW MUCH....Memory -HOW MUCH
And 48 ceramic pots per aircraft....well, it'd cost MEGABUCKS to make a few thousand a year, 'cos they'd be very special ceramic, dontcha know
